The Reflection of Ultrasound Waves/The Dispersion of Ultrasound Waves
©Walter Rasmussen, R.D.C.S.
A reflected ultrasound beam has the highest intensity when a structure presents a surface that is relatively smooth and perpendicular to the beam. There are however, many situations where the area of interest has a rough surface and is other than 90 degrees to the axis of the ultrasound beam and moving the transducer to an ideal position is not an option. The intensity of most ultrasound reflections are derived from scattered ultrasound due to the roughness of the surfaces being scanned and other tissue characteristics such as density and elasticity.
For example, from the apical window, the left ventricular lateral wall will tend to disperse the ultrasound away from transducer because it is almost parallel to the ultrasound beam. This often requires a higher gain setting and/or a reduction of frequency in order to amplify the low intensity, scattered reflections. In this situation, moving the transducer to an, “off axis,” position can help to provide stronger reflections off of the lateral wall.
RETURN to Home Page